Process for alkoxylation in the presence of rare earth triflimides

ABSTRACT

Disclosed is a process for making alkoxylates of organic compounds. The process requires a) providing an active hydrogen organic compound having 1 to 22 carbon atoms and b) alkoxylating the organic compound with an alkylene oxide in the presence of a catalytically effective amount of a rare earth triflimide of the following formula: 
     
       
         R 1 R 2 R 3 X 
       
     
     wherein X is a lanthanide; R 1 , R 2 , and R 3  each being independently a triflimide group of the following formula: 
     
       
         N(SO 2 Z) 2   
       
     
     wherein Z is C n F 2n+1 ; C being a carbon atom; F being a fluorine atom; and n being an integer from 1 to 15.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a process for making alkoxylates of narrowmolecular weight distribution. More particularly, the invention relatesto a process for alkoxylation in the presence of a catalyst of rareearth triflimides.

2. Background of the Invention

Nonionic Surfactants are industrially manufactured by reaction of aorganic compound with ethylene oxide using a base as catalyst e.g.sodium or potassium hydroxide. Nonionic surfactants are commonlymanufactured from the ethoxylation of fatty alcohols.

When a relatively low degree of ethoxylation, i.e. one to four moles, isdesired, an undesirably broad molecular weight product distribution isobtained. The broad distribution is due to the similar basicity of thealcohol and ethoxylate. Additive ethoxylation proceeds at the expense ofethoxylation of alcohol. Consequently, low mole ethoxylate productstypically have relatively large amounts of unreacted alcohol. Residualalcohol in the product presents odor problems and reduces the smokepoint. A low smoke point is especially problematic during thespray-drying of powdered detergents containing ethoxylated nonionicsurfactants, when a low smoke point may result in undesirablevolatilization of the surfactants.

In addition to higher smoke points and lower odor, ethoxylates of narrowmolecular weight distribution have performance advantages overethoxylates of broad molecular weight distribution. They include thefollowing: (i) lower viscosity and pour point for easier handling; (ii)higher cloud point; (iii) higher initial foaming and less foamstability; (iv) better wetting properties; (v) increased interfacialsurface tension reduction compared to paraffin; and (vi) higher surfacetension than conventional ethoxylates.

Various processes have been proposed in the base catalysis art to reducethe molecular weight distribution of alkoxylates. Such art is seen, forexample, in U.S. Pat. Nos. 3,471,411; 3,969,417; 4,112,231; 4,210,764;4,223,163; 4,223,164; 4,239,917; 4,278,820; 4,302,613; 4,306,093;4,360,698; 4,396,779; 4,453,022; 4,465,877; 4,453,023; 4,456,773;4,456,697; 4,721,817; 4,727,199; 4,754,075; 4,764,567; 4,775,653;4,885,009; 4,832,321 and 5,220,046, which are incorporated herein byreference. However, the art has to date failed to propose a basecatalysis process for making alkoxylates of sufficiently narrowmolecular weight distribution.

One means for making alkoxylates of narrower molecular weightdistribution is to employ acid catalysis to effect polymerization. Acidcatalysis has been generally disfavored, however, in the art because ofthe formation of relatively high levels of undesirable by-products. Forinstance, polyoxyethylene is formed by competing dehydration reactionsand dioxane and 2-methyldioxolane are formed by competing cyclizationreactions.

Processes for making alkoxylates of narrow molecular weight range withcatalysts of rare earth metals have been proposed. U.S. Pat. Nos.5,057,627 and 5,057,628 disclose processes for making alkoxylates ofnarrow molecular weight range with catalysts of monometallic salts ofrare earth elements. U.S. Pat. No. 5,059,719 discloses processes formaking alkoxylates with basic rare earth compounds such as rare earthalkoxides. U.S. Pat. No. 5,641,853 discloses the polymerization ofoxetanes, 1,3-dioxolanes, 1,3,5-trioxanes and tetrahydrofurans to linearpolyethers with metal compounds such as rare earth triflates andperfluoroalkylsulfonates. U.S. Pat. No. 5,677,412 discloses thepolymerization of cyclic ethers and organic isocyanates catalyzed bymetal compounds such as transition metal and rare earthperfluoroalkylsulfonates and rare earth triflates. EP 855417 discloses aprocess for making ethoxylates from a hydrogen labile compound and aalkyleneoxide using perfluoroalkylsulfonate salts of transition metalsor rare earths. Rare earth triflates are preferred. Rare earth catalystshave afforded the production of ethoxylates of narrower molecular weightdistribution with a lower degrees of residual active hydrogen organicstarting material, i.e. an alcohol.

In view of the foregoing, it would be desirable to have a new andeffective process for making alkoxylates of still narrower molecularweight distribution. Further, it would be desirable to have a processwhich afforded a still lower degree of residual active hydrogen organicstarting material. Still further, it would be desirable to have aprocess which afforded a lower degree of undesirable by-products.

SUMMARY OF THE INVENTION

It is an object of the present invention to produce alkoxylated organiccompounds of narrow molecular weight distribution.

It is a further object of the present invention to produce alkoxylatedorganic compounds and leave relatively low proportions of residualstarting materials.

It is a further object of the present invention to produce alkoxylatedorganic compounds with relatively low proportions of undesirableby-products.

It is still a further object of the present invention to provide aprocess for making alkoxylates of active hydrogen organic compounds. Theprocess requires (a) providing an active hydrogen organic compoundhaving an alkyl group of about 8 to about 20 carbon atoms and (b)alkoxylating the organic compound in the presence of a catalyticallyeffective amount of a rare earth triflimide of the following formula:

R¹R²R³X

wherein X is selected from the group of lanthanides, consisting morespecifically of neodymium, ytterbium, gadolinium, lanthanum, cerium,praseodymium, samarium, europium, terbium, dysprosium, erbium, thulium,and lutetium. R¹, R², and R³ are each independently a triflimide groupof the following formula:

N(SO₂Z)₂

wherein Z is C_(n)F_(2n+1). C is a carbon atom and F is a fluorine atom.“n” is an integer from 1 to 15. Z is preferably CF₃.

DETAILED DESCRIPTION OF THE INVENTION

In the process of the present invention, it was found unexpected thatalkoxylates of narrow molecular weight distribution could be preparedusing a catalyst of rare earth triflimides. It was also surprising thatsuch alkoxylates could be prepared leaving a relatively low degrees ofresidual active hydrogen organic starting material and undesirableby-products.

The rare earth triflimide catalysts useful in the present invention areof the following formula:

R¹R²R³X

wherein X is selected from the group of lanthanides, consisting morespecifically of neodymium, ytterbium, gadolinium, lanthanum, cerium,praseodymium, samarium, europium, terbium, dysprosium, erbium, thulium,and lutetium. R¹, R², and R³ are each independently a triflimide groupof the following formula:

N(SO₂Z)₂

wherein Z is C_(n)F_(2n+1). C is a carbon atom and F is a fluorine atom.“n” is an integer from 1 to 15. Z is preferably CF₃.

Preferred rare earth triflimides are those of neodymium, ytterbium andgadolinium. Corresponding formulas for the preferred triflimides areNd[N(SO₂CF₃)₂]₃, Yb[N(SO₂CF₃)₂]₃ and Gd[N(SO₂CF₃)₂]₃.

Rare earth triflimides can be prepared by reaction of rare earth oxidesand bistrifluoromethane sulfonamide acid. For instance, the preparationof lanthanum triflimides is shown in the following reactions:

 Ln₂O₃+6(CF₃SO₂)₂NH→2Ln[N(SO₂CF₃)₂]₃+3H₂O

or

Ln₂(CO₃)₃+6(CF₃SO₂)₂NH→2Ln[N(SO₂CF₃)₂]₃+3CO2

The rare earth triflimide catalyst is employed in a catalyticallyeffective amount. Preferably, the catalysts are employed at about1.0×10⁻⁵ M to about 1.0×10⁻¹ M based on the organic compound.

The active hydrogen organic compound employed in the present process has1 to 22 carbon atoms. Useful active hydrogen organic compounds includealcohols, amines, mercaptans and amides. Preferred compounds arehydrophobic and have from 8 to 22 carbon atoms. Preferred compounds arealso hydroxylated. Preferred compounds include fatty alcohols. Fattyalcohols can be obtained from natural sources such as fats and oils ormay be derived synthetically from petroleum. Natural alcohols areprepared from natural fatty acids derived from coconut oil, palm kerneloil, palm oil, tallow, soya, sperm oils and the like. Useful fattyalcohols include octanol, nonanol, decanol, dodecanol, palmityl alcohol,octadecanol, eicosanol, behenyl alcohol, and stearyl alcohol andmixtures or blends of the foregoing. A most preferred fatty alcohol isdodecanol. Unsaturated alcohols such as oleoyl, linoleic and linolenicalcohols are also useful. Synthetic alcohols may be prepared using theoxo (hydroformylation of carbon monoxide and hydrogen) or the Ziegler(ethylene and triethylaluminum) processes. Typical alcohols areoxodecyl, oxotridecyl, oxotetradecyl alcohol. Useful alcohols includeNeodol 23, 25 and 91 (Shell Corp.). Aromatic alcohols are also useful.Typical aromatic alcohols are nonylphenol, octylphenol,diisobutylphenol, dodecylphenol and dinonylphenol. Useful low molecularweight alcohols include methanol, ethanol, propanol, butanol and otherC₁ to C₇ alcohols.

Alkoxylation is carried out by contacting the active hydrogen organiccompound with an alkylene oxide under catalytically effectiveconditions. The reaction is carried out in the presence of the rareearth triflimides, which are Lewis acids. The alkoxylation reaction canbe carried out in temperature conditions from about 20° C. to 200° C.

Alkoxylation include the reactions of ethoxylation, propoxylation, andbutoxylation. Alkoxylation reactions involving adducts of higher numbersof carbons are possible and within the scope of the invention. Usefulalkylene oxide reactants include but are not limited to ethylene oxide,propylene oxide, butylene oxide and cyclohexene oxide. An importantreaction industrially is ethoxylation, which typically involves theaddition of ethylene oxide to a organic compound. More specifically, animportant reaction is the ethoxylation of dodecanol.

The present process affords the production of product having relativelynarrow molecular weight distribution. Although not bound by anyparticular range or level of distribution, degrees of narrowing up toabout 95% are possible. Preferred degrees of narrowing range from about80 to about 95%. Degree of narrowing are determined according to theformula and method set forth below.

The present process affords advantages over conventional base catalysisof the prior art. The present process yields alkoxylated product ofconsiderably narrower molecular weight distribution than that producedby conventional base catalysis using potassium or sodium hydroxide.Further, the present process leaves a lower residual content of activehydrogen organic starting material, i.e. fatty alcohols, thanconventional base catalysis. Further, the present process can beeffected at a lower operating temperatures than with conventional basecatalysis. Still further, the present process can be effected with abouta tenth of the amount of catalyst normally employed in conventional basecatalysis.

The catalyst can be used as is or can be supported on a mineral chargesuch as silica, alumno, titanium dioxide and the like. The catalyst canbe left in the final product or be recycled after proper treatment.

The following are non-limiting examples of the present invention. Allpercentages are by weight unless indicated otherwise.

EXAMPLES

Ethoxylates were prepared according to the process of the presentinvention via catalysis with rare earth triflimides. The relativedegrees of narrowing, residual starting material content, and by-productcontent were measured. The results were compared to ethoxylates preparedvia conventional base catalysis.

The degree of narrowing was defined according to the following formula:${{Degree}\quad {of}\quad {Narrowing}\text{:}\quad {DN}} = {\sum\limits_{n = {{n\quad \max} - 2}}^{n = {{n\quad \max} - 2}}{Yi}}$

wherein

n max=the molar number of added ethylene oxide (or alkylene oxide) in anadduct accounting for a maximum proportion by weight in a total adduct.

Yi=proportion by weight of an adduct having “i” moles of added ethyleneoxide to a total weight of the adduct.

For degree of narrowing determinations, the gas chromatographic (GC)area % was used. The degree of narrowing is expressed as a percentage(%). The higher the percentage, the narrower the molecular weightdistribution. The formula and method are set forth in Narrow AlcoholEthoxylates, Annual Surfactants Reviews, vol. 2, Ed. D. R. Karsa (1999).

In the Examples herein, gadolinium triflimide was prepared according tothe following: (1) 2.24×10⁻³ moles of Gd₂O₃ in 5 ml of deionized wateris charged into a round bottom flask equipped with a condenser; (2) 34ml of 0.39 M aqueous solution of bistrifluoromethane sulfonamide acidacid is added; (3) the mixture is brought to reflux over one hour; (4)then the mixture is cooled to room temperature and filtered to eliminateexcess oxide; (5) water is evaporated; (6) 20 ml of ethanol is added andthen evaporated; (7) the above step is repeated twice (threeaddition/evaporation steps total). Drying (evaporation) is performedunder vacuum over 24 hours at 72 millibars pressure at 70° C. Theresulting powder is used as soon as possible after drying, preferablyunder inert atmosphere, or stored under inert atmosphere.

Neodymium triflimide is prepared in the same manner as for gadoliniumtriflimide except that Nd₂O₃ was substituted for Gd₂O₃. In addition, theneodymium triflimide is not dried.

Comparative Example (R-111-132)

In this comparative example, ethylene oxide was reacted with dodecanolon a 3:1 mole basis in the presence of a potassium hydroxide catalyst.Dodecanol (Aldrich, 98%+Reagent) at 199.7 grams (gm) (1.07 moles) andpotassium hydroxide at 3.56 gm (45%, 1.6 gm of 100%) of were charged toa two liter autoclave. The autoclave was heated with nitrogen sparge to120° C. The autoclave was vacuum stripped for one hour with a slightnitrogen sparge. The vacuum was secured, then the reactor waspressurized to 20 psi with nitrogen and heated to 150° C. Ethylene oxide(141.5 gm) was added to the reactor over a one hour period at 150° C.and 50 pounds per square inch gauge (psig) and held for an additionalhour. The reactor was cooled to 120 ° C. and vacuum stripped for 10minutes. The reactor was then cooled further and 321 gm of productdischarged. Reaction conditions and results are set forth in the Table.

Example 1 (R-111-129)

In this example, ethylene oxide was reacted with dodecanol on a 3:1 molebasis in the presence of a neodymium triflimide catalyst. Dodecanol(Aldrich) at 200.1 gm (1.08 moles) and containing 2.89×10⁻³ M ofneodymium triflimide was charged to a 2 liter autoclave. The reactor washeated to 110° C. with a nitrogen sparge. The reactor was vacuumstripped for one (1) hour at 110° C. with a slight nitrogen bleed. Thereactor was then pressurized to 20 psig with nitrogen and 140.5 gm (3.22M) of ethylene oxide was added over three hours and ten minutes at 50psig. The reactor was stripped at 110° C. for fifteen minutes at a 3-4psig vacuum. The reactor was cooled to room temperature and 300 gm ofproduct was discharged.

Reaction conditions and results are set forth in the Table. Theethoxylate product exhibited a higher degree of narrowing (92% versus62.5%) and a lower residual alcohol content (1.6% versus 12.6%) than theComparative Example.

Example 2 (R-111-142)

Example 2 was carried out in the same manner as for Example 1. Threemoles of ethylene oxide were added per mole of dodecanol. In Example 2,10% molar of di-ter-butylpyridine (DBTP) was added as a proton trap.Results are set forth in the Table.

The ethoxylated product of Example 2 exhibited a higher degree ofnarrowing and a lower amount of residual dodecanol than the ComparativeExample.

Example 3 (R-111-95) and Example 4 (R-111-98)

Examples 3 and 4 were carried out in the same manner as for Example 1.Gadolinium triflimide was employed in Example 3 and neodymium triflimidewas employed in Example 4. Seven moles of ethylene oxide were added permole of dodecanol. Results are set forth in the Table.

The ethoxylated products of both Examples 3 and 4 both exhibited higherdegrees of narrowing and lower amounts of residual dodecanol than theComparative Example.

TABLE Catalyst Degree Amount Of (mole %) Narrow- Dio- Dode- in dode-Reaction Ing xane canol PEG Reference Catalyst canol Time Color (%) (wt.%) (wt. %) (wt. %) R-111-132* KOH 2.64 52 pale 62.5 0.0018 12.6 1.7minutes yellow R-111-129 Nd(TfSi)₃ 0.264 3 hours colorl 91 0.3 1.6 0.8ess R-111-142 Nd(TfSi)₃ + 0.264 3 hours yellow 92 0.4 1.7 1 DTBPR-111-95 Gd(TfSi)₃ 0.264 3 hours Light 83.5 1.6 0.12 7.1 brown R-111-98Nd(TfSi)₃ 0.264 3 hours Light 84 1.6 0.08 7 brown *Not an example of thepresent invention

It should be understood that the foregoing description is onlyillustrative of the present invention. Various alternatives andmodifications can be devised by those skilled in the art withoutdeparting from the invention. Accordingly, the present invention isintended to embrace all such alternatives, modifications and varianceswhich fall within the scope of the appended claims.

What is claimed is:
 1. A process for making alkoxylates of organiccompounds, comprising: a) providing an active hydrogen organic compoundhaving 1 to 22 carbon atoms and b) alkoxylating the active hydrogenorganic compound with an alkylene oxide in the presence of acatalytically effective amount of a rare earth triflimide of thefollowing formula: R¹R²R³X wherein X is a lanthanide; R¹, R², and R³each being independently a triflimide group of the following formula:N(SO₂Z)₂ wherein Z is C_(n)F_(2n+1); C being a carbon atom; F being afluorine atom; and n being an integer from 1 to
 15. 2. The process ofclaim 1, wherein the lanthanide is selected from the group consisting ofneodymium, ytterbium, gadolinium, lanthanum, cerium, praseodymium,samarium, europium, terbium, dysprosium, erbium, thulium, and lutetium.3. The process of claim 1, wherein the Z is CF₃.
 4. The process of claim1, wherein the rare earth triflimide is selected from the groupconsisting of gadolinium triflimide, neodymium triflimide, ytterbiumtriflimide.
 5. The process of claim 1, wherein the active hydrogencompound is selected from the group consisting of alcohols, amines,mercaptans and amides.
 6. The process of claim 5, wherein the organiccompound is a fatty alcohol having from 8 to 22 carbon atoms.
 7. Theprocess of claim 6, wherein the fatty alcohol is dodecanol.
 8. Theprocess of claim 1, wherein the catalyst is present at about 1.0×10⁻⁵ Mto about 1.0×10⁻¹ M based on the organic compound.
 9. The process ofclaim 1, wherein the alkoxylation is carried out at from about 20° C. to170° C.
 10. The process of claim 1, wherein the alkylene oxide isethylene oxide.
 11. The process of claim 1, wherein 1 to 100 moles ofalkylene oxide per mole of organic compound are reacted duringalkoxylation.
 12. The process of claim 1, wherein 2 to 4 moles ofalkylene oxide per mole of organic compound are reacted duringalkoxylation.
 13. The process of claim 1, wherein the rare earthtriflimide is selected from the group consisting of gadoliniumtriflimide, neodymium triflimide, ytterbium triflimide, the activehydrogen organic compound being a fatty alcohol having from 8 to 22carbon atoms, the alkylene oxide being ethylene oxide the catalyst beingpresent at about 1.0×10⁻⁵ M to about 1.0×10⁻¹ M based on the activehydrogen organic compound, the alkoxylation being carried out at fromabout 20° C. to 170° C., 1 to 100 moles of alkylene oxide per mole offatty alcohol are reacted during alkoxylation.
 14. The process of claim13, wherein the fatty alcohol is dodecanol.
 15. The process of claim 14,wherein 2 to 4 moles of alkylene oxide per mole of fatty alcohol arereacted during alkoxylation.